[Gluster-users] Gluster and LVM

[Felix Kölzow]

Thank you very much for your response.

I fully agree that using LVM has great advantages. Maybe there is a
misunderstanding,

but I really got the recommendation to not use (normal) LVM in
combination with gluster to

increase the volume. *Maybe someone in the community has some good or
bad experience*

*using LVM and gluster in combination.* So please let me know :)


> One of the arguments for things like Gluster and Ceph is that you can
> many storage nodes that operate in parallel so that the ideal is a
> very large number of small drive arrays over a small number of very
> large drive arrays.
I also agree we that. In our case, we actually plan to get Redhat
Gluster Storage Support and an increase of

storage nodes would mean an increase of support costs while the same
amount of storage volume is available.

So we are looking for a reasonable compromise.

Felix

On 03.04.19 17:12, Alvin Starr wrote:
> As a general rule I always suggest using LVM.
> I have had LVM save my career a few times.
> I believe that if you wish to use Gluster snapshots then the
> underlying system needs to be a thinly provisioned LVM volume.
>
> Adding storage space to an LVM is easy and all modern file-systems
> support online growing so it is easy to grow a file-system.
>
> If you have directory trees that are very deep and wide then you may
> want to put a bit of thought into how you configure your Gluster
> installation.
> We have a volume with about 50M files and something like an xfs dump
> or rsync of the underlying filesystem will take close to a day but
> copying the data over Gluster takes weeks.
> This is a problem with all clustered file systems because there is
> extra locking and co-ordination required for file operations.
>
> Also you need to realize that the performance of something like the
> powervault is limited to the speed of the connection to your server.
> So that a single SAS link is limited to 6Gb(for example) and so is
> your disk array but most internal raid controllers will support the
> number of ports * 6Gb.
> This means that a computer with 12 drives in the front will access
> disk faster than a system with a 12 drive disk array attached by a few
> SAS links.
>
> One of the arguments for things like Gluster and Ceph is that you can
> many storage nodes that operate in parallel so that the ideal is a
> very large number of small drive arrays over a small number of very
> large drive arrays.
>
>
> On 4/3/19 10:20 AM, kbh-admin wrote:
>> Hello Gluster-Community,
>>
>>
>> we consider to build several Gluster-servers and have a question
>> regarding  lvm and Glusterfs.
>>
>>
>> Scenario 1: Snapshots
>>
>> Of course, taking snapshots is a good capability and we want to use
>> lvm for that.
>>
>>
>> Scenaraio 2: Increase Gluster volume
>>
>> We want to increase the Gluster volume by adding hdd's and/or by adding
>>
>> dell powervaults later. We got the recommendation to set up a new
>> Gluster volume
>>
>> for the powervaults and don't use lvm in that case (lvresize ....) .
>>
>>
>> What would you suggest and how do you manage both lvm and Glusterfs
>> together?
>>
>>
>> Thanks in advance.
>>
>>
>> Felix
>>
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>> Gluster-users at Gluster.org
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>
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